uPVC sash windows, also called vertical sliders, give you the classic look of a traditional sash and case window without the painting and rot. They’re low-maintenance, but not no-maintenance. A little care a few times a year keeps the sashes sliding smoothly, the seals tight and the locks working.
This guide covers modern uPVC vertical sliders. Traditional timber sash and case windows, common in Glasgow tenements, need different care such as painting and sash cord repairs. For those, Historic Environment Scotland’s guidance on sash and case windows is the best place to start. For your other windows and doors, see our guide to maintaining uPVC windows and doors.
Windows facing the prevailing wind and rain, or on upper floors where dirt builds up unseen, may need attention more often.
Most modern uPVC sash windows have sashes that tilt inwards, so you can clean the outside of the glass from inside the room. That’s much safer than leaning out or using a ladder, especially on upper floors.
To tilt a sash in, the usual method is:
Mechanisms vary between manufacturers, so check your window’s instructions if it doesn’t move easily. Never force a sash. Our guide to opening uPVC windows fully for cleaning covers other window types too.
Once it’s open:
The bottom of the outer frame has small drainage slots that let rainwater escape. When leaves, dirt or spider webs block them, water can pool in the frame and find its way inside.
Clear them twice a year with a soft brush, a pipe cleaner or a thin piece of wire. On a dry day, a small cup of water poured along the bottom of the frame should drain away quickly. If it sits there, a slot is still blocked.
The locks, tilt latches and side channels need a light lubricant now and then to keep everything moving freely.
uPVC sash windows usually use brush pile seals, a strip of tightly packed fibres, along the edges where the sashes meet the frame and each other. These seals keep draughts and rain out while letting the sashes slide.
Once a year, check them for:
Worn brush seals can be replaced, but they come in specific sizes for each window system, so it’s often easiest to have an installer do it. If draughts are a problem, our 6 steps to stop draughts around uPVC windows may help. Good seals also make a big difference to heat loss; the Energy Saving Trust’s guide to windows and doors explains why.
While you’re checking, look at the silicone around the outside of the frame where it meets the wall. If it has cracked or pulled away, it needs redoing to keep rain out.
Cleaning, clearing drainage slots and light lubrication are easy jobs for most homeowners. Call a professional if:
If your windows are past repair, or you’re thinking about replacing old timber sashes, see our uPVC sash windows in Glasgow page.
Most modern uPVC sash windows tilt inwards. Unlock the window, raise the lower sash slightly, slide the two tilt latches at the top towards the centre and pull the sash gently towards you. You can then clean the outside of the glass from inside the room.
A silicone spray or dry PTFE spray on the locks, tilt latches and side channels. Avoid oil and grease, which attract dirt, and don’t lubricate the spring balances.
The spring balance in the side of the frame has usually worn or broken. Balances can be replaced, but because they’re under tension and matched to the sash weight, it’s best done by a professional.
The seal on the double-glazed unit has failed and moist air has got between the panes. The glass unit needs replacing; the frame can usually stay.
No. uPVC doesn’t need painting or sealing like timber. Regular cleaning, clear drainage slots and occasional lubrication are all it needs.
Whether your sash windows need a repair or you’re ready to replace them, our team can help. Call us on 07723 363366 or request a free, no-obligation quote.
